Case Report: A rare case of small bowel obstruction secondary to plasma cell myeloma

Abstract

Gastrointestinal (GI) involvement of plasma cell neoplasms is extremely rare. Herein, we describe the case of a 74-year-old Caucasian woman who came to our attention with abdominal pain, food vomiting, and weight loss of 10 kg over 1 year. A computed tomography scan of the abdomen revealed circumferential thickening of terminal ileum, for which the patient underwent an urgent 20-cm-long ileal resection. Histopathological and immunophenotypic analysis revealed a plasma cell neoplasm of the ileum. Subsequent investigations found a serum monoclonal immunoglobulin A component, an osteolytic lesion of the left jaw, and a clonal bone marrow plasma cell infiltrate carrying 1q21 amplification. Given the final diagnosis of plasma cell myeloma (PCM), the patient underwent a VMD (bortezomib, melphalan, and dexamethasone) chemotherapy regimen, achieving a complete remission after a 12-month treatment. For disease relapse, two further chemotherapy regimens were later attempted. At the last follow-up 4 years after the diagnosis, the patient is still alive. This case draws attention to the extramedullary presentation of plasma cell neoplasms, even if rare, as a prompt diagnosis seems to result in a better prognosis. In addition, it highlights the relevance of a multidisciplinary approach, involving gastroenterologists, hematologists, and pathologists, to the diagnosis and management of these neoplasms.

Keywords: chemotherapy; extramedullary presentation; intestinal occlusion; plasma cell myeloma; small bowel.

Figure 1

Abdominal computed tomography scan showing wall circumferential thickening (delimited by the pointer) at terminal ileum.

Figure 2

Histological and immunohistochemical features of ileal resection specimen. Hematoxylin-eosin staining (A) shows ileal wall infiltrated by a proliferation of pleomorphic plasma cells. Immunohistochemical staining presented CD138⁺ (B), MUM1⁺ (C), IgA⁺ (D), and monoclonal restriction for Kappa light chain of Ig (E), whereas Lambda light chains of Ig tested negative (F). The proliferative index (Mib1/Ki67) was around 40% (G).

Figure 3

Histological and immunohistochemical features of bone marrow biopsy. Hematoxylin-eosin staining (A) shows a plasma cell infiltrate, accounting for 15% of bone marrow cellularity. Immunohistochemical staining presented CD138⁺ (B), with restriction for Kappa light chain of Ig (C). Neoplastic plasma cells also aberrantly expressed CD56 (D), whereas immunohistochemistry for Lambda light chain resulted completely negative (E).